Label-free quantitative proteomic analysis reveals the characteristics of ovarian development from stage II to III in Chinese sturgeon (Acipenser sinensis)

Chinese sturgeon ( Acipenser sinensis ) is an endangered anadromous and rare fish. The ovary development from stage II to III is being challenged by captive conditions, which seriously hinders the artificial reproduction of Chinese sturgeon. A comparative proteomic analysis on the ovaries at stage II and stage III of Chinese sturgeon was conducted in this study using the label-free quantitative method to uncover the intricate physiological processes . The findings revealed 200 up-regulated differentially expressed proteins (DEPs) and 150 down-regulated DEPs in the ovary at stage III compared with stage II, and 11 DEPs (including UCHL1 , VTG , CTSD , and ZP , etc.) involved in the vitellogenesis and oocyte growth . Moreover, the up-regulated DEPs exhibited significant enrichment in the pathways linked to protein synthesis (ribosome, protein processing in the endoplasmic), metabolism and energy production (valine, leucine and isoleucine degradation, TCA cycle, oxidative phosphorylation , and fatty acid degradation), suggesting more active protein processing and energy metabolism at stage III. Meanwhile, APOB was down-regulated while VTG was up-regulated in stage III ovary, indicating the uptake of yolk protein and lipid through VTG at this stage. The parallel reaction monitoring (PRM) quantification of 16 DEPs solidly validated the outcomes of label-free analysis. This study provided powerful information for understanding the physiological processes of ovarian development in Chinese sturgeon, and potential biomarkers in predicting the vitellogenic stage. • Protein expression pattern of Chinese sturgeon ovaries at stage II and III was revealed. • 11 DEPs related to ovarian development of Chinese sturgeon were found. • Some key DEPs involved in transport, metabolism, and energy production. • 16 DEPs were validated of label-free quantitative proteomic results by PRM.